As is disclosed in, for example, Patent Document No. 1, in a vehicle, there is a configuration in which right and left side members (FR, FL in FIGS. 1 and 2 of Patent Document No. 1) are disposed in a longitudinal direction at a front lower part of a vehicle body, and a subframe (FS in FIGS. 1 and 2 of Patent Document No. 1) is connected to the right and left side members in such a manner as to extend therebetween, so that suspension arms (11 in FIGS. 1 and 2 of Patent Document No. 1) for supporting front wheels are supported on the subframe.
In Patent Document No. 1, at one supporting portion of a plurality of supporting portions of the subframe which support the suspension arm, an upper receiving portion (21, 22, 22a in FIGS. 2 and 5 of Patent Document No. 1) is provided on the subframe in such a manner as to extend transversely outwards, and a lower receiving portion (33 in FIGS. 2 and 5 of Patent Document No. 1) is provided on the subframe at a predetermined downward interval from the upper receiving portion on the subframe in such a manner as to extend transversely outwards. By this configuration, a suspension arm is made to be supported on the subframe via a rubber bushing joint (13 in FIGS. 2 and 5 of Patent Document No. 1) by a connecting bolt (34 in FIGS. 2 and 5 of Patent Document No. 1) which passes vertically through the upper and lower receiving portions of the subframe.
Patent Document No. 1: JP-A-2002-370670
In recent years, to reduce the weight of the subframe, it is considered that a subframe is formed of a light metal. When a subframe is formed of a light metal like this, in the event that a configuration as is described in Patent Document No. 1 is adopted in which an upper receiving portion (21, 22, 22a in FIGS. 2 and 5 of Patent Document No. 1) is provided on the subframe in such a manner as to extend transversely outwards, and a lower receiving portion (33 in FIGS. 2 and 5 of Patent Document No. 1) is provided on the subframe at a predetermined downward interval from the upper receiving portion on the subframe in such a manner as to extend transversely outwards, the space defined between the upper and lower receiving portions of the subframe needs to match a vertical length of a rubber bushing joint (a base portion of a suspension arm) with good accuracy.
To describe this in other words, after the subframe is formed of, for example, a light metal, in the event that the space defined between the upper and lower receiving portions of the subframe is larger than the vertical length of the rubber bushing joint (the base portion of the suspension arm), a force is produced which attempts to bend the lower receiving portion of the subframe upwards by tightening a connecting bolt, leading to a risk that a crack is produced in the vicinity of the lower receiving portion of the subframe. Consequently, after the subframe is formed of the light metal, machining needs to be applied to the upper and lower receiving portions of the subframe so that the space defined between the upper and lower receiving portions of the subframe matches the vertical length of the rubber bushing joint (the base portion of the suspension arm) with good accuracy.
Furthermore, in a case where a subframe is formed through die-casting, when attempting to have a configuration as is described in Patent Document No. 1 in which an upper receiving portion is provided on the subframe in such a manner as to extend transversely outwards, and a lower receiving portion is provided on the subframe at a predetermined downward interval from the upper receiving portion on the subframe in such a manner as to extend transversely outwards, the upper and lower receiving portions cannot be integrally formed on the subframe through die-casing unless a slide mold is used.